# Introduction

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# Open-Unmix - A Reference Implementation for Music Source Separation

Open-Unmix, is a deep neural network reference implementation for music source separation, applicable for researchers, audio engineers and artists. Open-Unmix provides ready-to-use models that allow users to separate pop music into four stems: vocals, drums, bass and the remaining other instruments.

Although open-unmix reaches state of the art separation performance as of September, 2019 (See Evaluation), the design choices for it favored simplicity over performance to promote clearness of the code and to have it serve as a baseline for future research. The results are comparable/better to those of UHL1/UHL2 which obtained the best performance over all systems trained on MUSDB18 in the SiSEC 2018 Evaluation campaign (opens new window). We designed the code to allow researchers to reproduce existing results, quickly develop new architectures and add own user data for training and testing. We favored framework specifics implementations instead of having a monolithic repository with common code for all frameworks.

The model is available for three different frameworks. However, the pytorch implementation serves as the reference version that includes pre-trained networks trained on the MUSDB18 (opens new window) dataset.

# ⭐️ News

  • 03/07/2021: We added umxl, a model that was trained on extra data which significantly improves the performance, especially generalization.

  • 14/02/2021: We released the new version of open-unmix as a python package. This comes with: a fully differentiable version of norbert (opens new window), improved audio loading pipeline and large number of bug fixes. See release notes (opens new window) for further info.

  • 06/05/2020: We added a pre-trained speech enhancement model umxse provided by Sony.

  • 13/03/2020: Open-unmix was awarded 2nd place in the PyTorch Global Summer Hackathon 2020 (opens new window).

# Paper

Open-unmix is presented in a paper that has been published in the Journal of Open Source Software. You may download the paper PDF here (opens new window)

If you use open-unmix for your research, please cite it through the references below.

# Design Choices

The design choices made for Open-Unmix have sought to reach two somewhat contradictory objectives. Its first aim is to have state-of-the-art performance, and its second aim is to still be easily understandable, so that it can serve as a basis for research to allow improved performance in the future. In the past, many researchers faced difficulties in pre- and post-processing that could be avoided by sharing domain knowledge. Our aim was thus to design a system that allows researchers to focus on A) new representations and B) new architectures.

# Framework specific vs. framework agnostic

We choose pytorch to serve as a reference implementation due to its balance between simplicity and modularity. Furthermore, we already ported the core model to NNabla (opens new window). Note that the ports will not include pre-trained models as we cannot make sure the ports would yield identical results, thus leaving a single baseline model for researchers to compare with.

# "MNIST-like"

Keeping in mind that the learning curve can be quite steep in audio processing, we did our best for Open-unmix to be:

  • simple to extend: The pre/post-processing, data-loading, training and models part of the code are isolated and easy to replace/update. In particular, a specific effort was done to make it easy to replace the model.
  • hackable (MNIST like): Due to our objective of making it easier for machine-learning experts to try out music separation, we did our best to stick to the philosophy of baseline implementations for this community. In particular, Open-unmix mimics the famous MNIST example, including the ability to instantly start training on a dataset that is automatically downloaded.

# Reproducible

Releasing Open-Unmix is first and foremost an attempt to provide a reliable implementation sticking to established programming practice as were also proposed in (McFee et al. 2018). In particular:

  • reproducible code: everything is provided to exactly reproduce our experiments and display our results.
  • pre-trained models: we provide pre-trained weights that allow a user to use the model right away or fine-tune it on user-provided data (Stöter and Liutkus 2019a, 2019b).
  • tests: the release includes unit and regression tests, useful to organize future open collaboration through pull requests.

# 🏁 Getting started

# Installation

openunmix can be installed from pypi using:

pip install openunmix

Note, that the pypi version of openunmix uses [torchaudio] to load and save audio files. To increase the number of supported input and output file formats (such as STEMS export), please additionally install stempeg (opens new window).

Training is not part of the open-unmix package, please follow [docs/train.md] for more information.

# Using Docker

We also provide a docker container. Performing separation of a local track in ~/Music/track1.wav can be performed in a single line:

docker run -v ~/Music/:/data -it faroit/open-unmix-pytorch umx "/data/track1.wav" --outdir /data/track1

# Pre-trained models

We provide three core pre-trained music separation models. All three models are end-to-end models that take waveform inputs and output the separated waveforms.

Furthermore, we provide a model for speech enhancement trained by Sony Corporation

All four models are also available as spectrogram (core) models, which take magnitude spectrogram inputs and ouput separated spectrograms. These models can be loaded using umxl_spec, umxhq_spec, umx_spec and umxse_spec.

To separate audio files (wav, flac, ogg - but not mp3) files just run:

umx input_file.wav --model umxl

A more detailed list of the parameters used for the separation is given in the inference.md document.

We provide a jupyter notebook on google colab (opens new window) to experiment with open-unmix and to separate files online without any installation setup.

# Using pre-trained models from within python

We implementes several ways to load pre-trained models and use them from within your python projects:

# When the package is installed

Loading a pre-trained models is as simple as loading

separator = openunmix.umxhq(...)

# torch.hub

We also provide a torch.hub compatible modules that can be loaded. Note that this does not even require to install the open-unmix packagen and should generally work when the pytorch version is the same.

separator = torch.hub.load('sigsep/open-unmix-pytorch', 'umxhq', device=device)

Where, umxhq specifies the pre-trained model.

# Performing separation

With a created separator object, one can perform separation of some audio (torch.Tensor of shape (channels, length), provided as at a sampling rate separator.sample_rate) through:

estimates = separator(audio, ...)
# returns estimates as tensor

Note that this requires the audio to be in the right shape and sampling rate. For convenience we provide a pre-processing in openunmix.utils.preprocess(..)` that takes numpy audio and converts it to be used for open-unmix.

To perform model loading, preprocessing and separation in one step, just use:

from openunmix import separate
estimates = separate.predict(audio, ...)

# Contribute / Support

open-unmix is a community focused project, we therefore encourage the community to submit bug-fixes and requests for technical support through github issues (opens new window). For more details of how to contribute, please follow our CONTRIBUTING.md (opens new window).

For support and help, please use the gitter chat (opens new window) or the google groups (opens new window) forum.

# References

If you use open-unmix for your research – Cite Open-Unmix
  author        = {F.-R. St\\"oter and 
                   S. Uhlich and 
                   A. Liutkus and 
                   Y. Mitsufuji},  
  title         = {Open-Unmix - A Reference Implementation 
                   for Music Source Separation},
  journal       = {Journal of Open Source Software},  
  year          = 2019,
  doi           = {10.21105/joss.01667},
  url           = {https://doi.org/10.21105/joss.01667}

If you use the MUSDB dataset for your research - Cite the MUSDB18 Dataset

  author       = {Zafar Rafii and
                  Antoine Liutkus and
                  Fabian-Robert St{\"o}ter and
                  Stylianos Ioannis Mimilakis and
                  Rachel Bittner},
  title        = {The {MUSDB18} corpus for music separation},
  month        = dec,
  year         = 2017,
  doi          = {10.5281/zenodo.1117372},
  url          = {https://doi.org/10.5281/zenodo.1117372}

If compare your results with SiSEC 2018 Participants - Cite the SiSEC 2018 LVA/ICA Paper

  author       = {Fabian-Robert St{\"o}ter and
                  Antoine Liutkus and
                  Nobutaka Ito},
  title        = {The 2018 Signal Separation Evaluation Campaign},
  booktitle    = {Latent Variable Analysis and Signal Separation},
  year         = 2018,
  pages        = {293--30}

⚠️ Please note that the official acronym for open-unmix is UMX.

# Authors

Fabian-Robert Stöter (opens new window), Antoine Liutkus (opens new window), Inria and LIRMM, Montpellier, France

# License


# Funding

This work was partly supported by the research programme KAMoulox(ANR-15-CE38-0003-01) funded by ANR, the French State agency for re-search